Fabric structure for parachutes and aerostats and method of constructing the same



G. M. BALL.

FABRIC STRLICTURE FOR PARACHUTES AND AEROSTATS AND MLTHOD OF CONSTRUCTING THE SAME.

' APPLICATION FILED IYIAY5. 1921.

I 9 4%7372 Patented Spt. 5, 1922 Methods of 'Constructing the Same, of

Patented Sept. 5, 1922.

umrs stares rirEN r' OFFICE.

our M. BALL, or sroxann, WASHINGTON.

FABRIC srnuo'runn ron ranaonu'ras Ann annosrars AND METHOD or CON- srnuorme run sane.

Application filed May 5,

To all whom it may concern:

zen of the United States, residing atfipokane, in the county of Spokane and State of Washington, have invented certain new and useful Improvements in Fabric Structure for Parachutes and Aerostats and which the following is a specification.

My invention relates to the fabric structure of parachutes*"and the envelopes of aerostats, and to a method of constructing the same.

It is the primary object of the invention to provide a fabric structure which will be very strong, in which any ripping stress will be distributed over a large area, and in which such stress can only produce a rip of short extent. Heretofore, the only means relied upon to check ripping and limit its extent of action have been the seams b6-',

tween panels. The construction of the panels has been such that any stress applied to a seam was not absorbed but resulted genorally, in furtherripping. I have discovered that the faulty .feature*has been the arrangement of the warp and weftthreads of the fabric with one set of threads substantially at right angles to the seam 'between panels and the other set of threads R parallel to the jsame. Any stress upon a seam between panels has communicated 1ongitudinal stress to the threads which. are

perpendicular thereto and shearing stress to the parallel threads.'- As a result, instead of absorbing shock, the fabric structure of an affected panel has become torn. This failure to reinforce the same generally 'results in rupture of the seam, ifithat has not already occurred. Considering parachutes in particular, a radial "rip is not so serious as a lateral rip extending through more than one panel. In practice it has been found that a single panel'may. rip from vent hem to skirt hem withoutincreasing the speed of descent so materially as to result in a dangerous landing. Therefore, a fabric structure; which'w-ill restrict ripping to the panel in hi h it starts is desired.

In addition to providing a fabric structure which will prevent lateral ripping when appliedto parachute construction in par:v tijcula-r, it is an object also to provide .a structure which will tend to limit the extent of radial ripping. This has been accom- 1921. Serial a... 467,128.

plished in the past by the use of a series of lateral reinforcing bands Which intersect the interpanel. seams at relatively spaced polnts between vent and skirt.

A. further object is to provide a fabric structure which will accomplish the objects ust mentioned and which may be cut into panels for the construction of parachutes, balloon envelopes, and the like, with maximum economy of material.

Further objects and advantages may become apparent as the following specific description is read in connection with the accompanying drawing, in which:

Fig. 1 is 'a plan view of a parachute constructed in accordance with the present in-' their angular relation to adjoining seams;

and

merous other articles of manufacture which.

are subject to ripping stresses due to the effect of wind or other causes, may employ .in their construction the principlesyof the present invention with a view to limiting the extent of rips which may-1 occur... The scope of the invention istherefore not limited tothe illustrative disclosure in the accompanying drawings. 3

Referrin to Fig. 1 it will be oted that the parachute therei disclosed consists essentially of a pluralit; ofmain panels 5 and vent panels 6 extending between the skirt hem 7 and the vent Fig. 2 is a plan view of a strip of the im. proved fabric structure made up for parav. of the-drawings first,

hem 8. The main panels are connected to-- get-her at their, adjacent edges by the usual l interpanel seams 9 and'the vent panels are similarly joined by. interpanel seams 10. Theseare the general characteristics of a well-known type of parachute. The present invention may obviously be applied to other types of parachutes as well. It Wlll be observed that each panel is made up of a number of segments 11 which are sepa- 5 rated by diagonal seams 12. It will be noticed also that the intersegmental seams 12 of each panel are parallel to each other. This feature results from the method of uniting standard strips of material in the construction of the composite strips from which the panels are cut and will be more clearly described later or in connection with Fig. 2 of the drawing. The important feature is thediagonal arrangement of these seams, regardless of their incidental parallelism.

Turning to that portion of Fig. 1 in which the warp and weft threads of the fabric are shown in detail, it will be seen that the warp threads 13 are parallel to the intersegmental seams in each panel, the weft threads 14 being consequently at right angles to these seams. The seams 12 are preferably disposed at 45 to the axis of each panel. This brings the warp and weft threads into oblique angular relation to' adjacent interpanel seams. The functions performed by this relative arrangement of threads and seams will be described presentl I The intersegmental seams may be supplemerited by the usual lateral bands 15 as shown, but the former will be more effective in limiting the extent of lateral .rips that may occur.

The manner in which the relative ,arrangement of threads and scams functions will now be described. Assuming that some segment of a panel has become torn while theparachute is descending through the air,

the rip will be directed in an oblique direc-.

tion with respect to the panel axis rather than parallel to theyaxis. This is due to the oblique arrangement of the warp and weft threads. As a result, the rip will meet either an interpanel seam or an intersegmental seam, and will extend at an oblique angle to the interpanel seam, or at right angles to the intersegmental seam, as .the case may be. If the rip meets an interpanel seam, it will be stopped thereby, due to the fact that additional stress brought to bear upon the seam .will be absorbed by the fabric of the panel on the opposite side of the latter. The warp and weft threads of this last mentioned fabric are not disposed at, right rngles to the seam or parallel thereto, so the stress communicated to them will neither shear the parallel threads nor rupture the perpendicular threads by exerting excess endwise. pull on them. The threads are on the contrary disposed at an oblique angle to the same and the lateral stress on the panel will tend to change the angular relation of warp to weft threads and thus to make the fabric more impervious. This is not a disadvantage when occurring'only at one or two isolated points, so may be permitted. This distortion of the threads absorbs shock and distributes it over a considerable area without permitting rupture of the fabric. On the other hand, in the event that a rip encounters an intersegmental seam, the latter being very short as compared with an interpanel seam will exert lateral pull upon adjacent interpanel seams before being distorted to the breaking point. This latter stress upon interpanel seams will be distributed over the fabric of the two adjoining panels and will be absorbed in the manner just described. Therefore, the intersegmental seams will also serve to stop a rip. The effect of the whole arrangement is to restrict any ripping whichstarts to the extent of one of these small segments. One such rip, or even several, would not be dangerous. The parachute would still give suflicient support to the Weight carried thereby to retard the speed of descent below the danger point.

In Fig. 2 the method of making up a wide strip from which a series of panels may be out without Waste of material is represented. A strip of the desired fabric material of standard width, as it comes from the mills, is cut into a series of short strips 16. Each short strip is in the form of a rhombus. This isjaccomplished by cutting the standard strips at 45 so there will be no wastage. When the strips 16 are joined in the manner 100 shown, they will form wide composite strips n and will extend at 45 to the longitudinal axis of the latter. The width of the. composite'strip depends upon the length of the panels that are to be cut therefrom. For 105 the main panels of the parachute, for instance, the composite strip will be wider than it would be for the cutting out of vent panels. For the manufacture of parachutes of the specific type disclosed in Fig. 1 two llo composite strips will be required, whereas the number. of strips of various widths required for the construction of balloon envelopes, and other devices, will depend upon the requirements in each particular case.

The short strips 16 may be j cined together by means of seams 17 of suitable formation. The panels which are to be used in the final construction of the parachute or other device may be cut from this composite strip. In the present instance, the panels are trapezoidal in form and are out along lines 18 with the long and short bases alternating in position so as to economize material and prevent any wastage. When the segments are joined in the usual manner by means of suitable interpanel sea-ms, thedesired relative arrangement of the threads and seams will result.

It is desired again to emphasize the point'out the fact that various modifications in the arrangement of parts or other structural details may be resorted to in practice without departing from the scope of the appended claims.

I claim:

1. A fabric covering for aerial devices comprising a plurality of panelsof woven material secured together by seams at ad joining edges, each panel being made of a plurality of diagonally extending segments secured together by intersegmental seams at adjoining edges and said intersegmental seams of one panel being obliquely related to the intersegmental seams of adjacent panels. v

2. A fabric covering for aerial devices comprising a plurality of panels of Woven material'secured together by' seams at adj'oinin 'edges, each panel being made of a plurality ofdiagonally extending strips-secured together by seams at adjoining edges and arranged with corresponding threads parallel, the strips of one panel being oblique to the strips of adjacent panels.

3, The method of makingv a fabric structure which consists in forming a wide strip of woven material by joining together a plurality of narrow strips in diagonal relation to the axis of the wide strip, cutting transverse panels from thewide strip, and securing a plurality of panels together in such manner as to form the completed fabric structure in which the narrow strips-of one panel extend obliquely to the narrow strips of adjacent panels.

Intestimony whereof I have aflixed my si ature. GUY M. BALL. 

